Is La Coste, TX Tap Water Safe to Drink?
Graded A-, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
88.9/100
waterverge.com La Coste, TX — Water Quality Report
La Coste's drinking water received a grade of A- (88.9 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,488 residents using groundwater.
Lead levels were measured at 4.6 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 11 violations on record, including 0 health-based violations. 4 remain unresolved.
What to know about La Coste's water
La Coste ranks #69 out of 1067 cities in Texas for water quality, placing it one of the best in the state.
La Coste relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, La Coste may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is La Coste, TX water safe to drink?
La Coste's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (88.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,488 residents using groundwater (wells).
Recent water quality updates for La Coste
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into La Coste's water quality assessment. Grade: A- (88.9/100).
Contaminants: Lead and Copper Rule.
Contaminants: Chlorine.
Contaminants: Chlorine.
Federal disaster declaration (FEMA DR-3313). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1606). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for La Coste's water supply.
Well within EPA limits.
Violation history
La Coste's water system has 11 total violations on record, including 0 health-based violations. 4 remain unresolved.
Flood & environmental risk
Medina County has experienced 2 federally declared disasters since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Medina Rv At La Coste, Medina Rv Nr Macdona.
Where does La Coste's water come from?
La Coste's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,488 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Medina Rv At La Coste (river), Medina Rv Nr Macdona (river).
What La Coste residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in La Coste's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D3 — extreme droughtMedina County is currently in D3 (extreme drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Medina County has experienced 2 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 4.6 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how La Coste compares by contaminant
Explore where La Coste ranks among all Texas cities for specific contaminants.
Water source & infrastructure
Where La Coste's water comes from
La Coste's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 1,488 people through 1 water system.
Water bodies near La Coste
La Coste is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving La Coste
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CITY OF LA COSTE | TX1630004 | 1,488 | GW |
How La Coste compares
Full Texas rankings →La Coste's score of 88.9/100 is above the average of 46/100 among major Texas cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Texas rankings →About La Coste, TX
Wikipedia →La Coste is a city in Medina County, Texas, United States. As of the 2020 census, La Coste had a population of 1,077. It is part of the San Antonio Metropolitan Statistical Area.
Learn more about your water
Guides and resources related to La Coste's water quality findings.
Explore water quality across Medina
Frequently asked questions
Is La Coste, TX tap water safe to drink?
La Coste's water quality earned a grade of A- (88.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #69 out of 1067 cities tested in Texas.
What contaminants are in La Coste's water?
Lead was measured at 4.6 ppb (90th percentile). 11 violations are on record.
How is La Coste's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in La Coste?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does La Coste's water come from?
La Coste's water is sourced from Groundwater. The city has 1 water system serving approximately 1,488 residents.
Is La Coste's groundwater at risk of contamination?
La Coste uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 11 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does La Coste's water compare to other cities?
La Coste ranks #69 out of 1067 cities in Texas (better than 94% of state cities) and #3173 out of 15744 cities nationally (80th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does La Coste's small water system affect quality?
La Coste's system serves approximately 1,488 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 11 violations on record.